Safety system for motor-propelled cars.



PATENTED JUNE 12, 1906.

A lJ. E. MILLER. SAFETY SYSTEM EUR MoToE EEOEELLED GEES.

APPLICATION FILED NOV. 6, 1905.

@XT-1i @ooe Aim@ O f I Ma d n m m UNITED sTATEs PATENT oFFroE.

JOHN A. MILLER, OF BALTIMORE, MARYLAND, ASSIGNOR TO JOHN VM. THURSTON, TRUSTEE. OF WASHINGTON, DISTRICT OF COLUMBIA.

Speccaton of Letters Patent.

Patented J' une 12,1906.

Application tiled Novmber 6,1905. Serial No. 286.048.

-o @ZZ whom t may concern:

Be it known that I, JOHN A. MILLER, a citizen of the United States, residing at the city of Baltimore, in the State of Maryland, have invented lnew and useful Improvements in Safety Systems for Motor-Propelled Cars, of which the following is a specification.

This invention relates to an improved safety system for motor-propelled cars or vehicles, and while cal able: of application` to motor` cars or vehic es of any type having safety closures or gates the invention ossesses special utility as an electrical sa ety system or elevators.

To this end the invention contem lates a safety system or mechanism arrange to prevent the car from moving in the event of any of the safety doors or gates being opened, as well as providing means for arresting the car in the event of a safety door or gate becoming open during the travel of the car.

Also the invention comprises means for arresting the travel of the car in the event of v the same attaining a dangerous speed.'

A primary object of this invention is to provide a reliable method and means for -the accomplishinpnt of the above-mentioned purposes that is extremely simple in design and operation and comprises few working parts.

A further object of this invention is to provide an equipment that is adapted to be Aemployed in connection With any type of electrically-actuated elevator and which is inexpensive to install and that employs but a small amount of electric energy to operate the same, thereby insuring the highest economy in construction, operation, and maintev nance.

'A further object of this invention is to provide a safety-governing means for -a motor that is subject to the influence of adetectingcurrent in a normall closed safety-circuit in a manner whereby the said safety-governing means erforms not only its special or intended nctions, but is susceptible of revealing the failure of power or apparatus in said safety means-Ji. e., any failure of power or apparatus in the safety means is indlcated on the side of safety'by reason of the actuation of the lgoverning means and the consequent disconnection ofthe supply-current from the driving-motor and the a plication of the dynamic brake means emp oyed;

To these ends the invention comprehends primarily an electrically-actuated switch mechanism included in a normally closed Isafety-circuit in a manner to be responsive to.

the opening of said circuit to cause the disconnection of the main or supply circuit to the motor, and the application of an electrodynamic brake for the purpose of holding the armature of said motor from movement.

This invention is especially applicable to the type of elevator in which the oad is lifted by an electric motor and descends by gravity under the control of the same motor when the armature is reversed in direction of rotation.

Referring to the accompanying drawings, Figure 1 represents a diagrammatic view of the arrangement of the circuits and devices emplo ed. Fig. 2 represents in perspective the e ectrically-actuated master-switch or safety-circuit controlled governing means. Fig. 3 represents a simple t rpe of openin and closing attachment for doors employe in connection with the safety-circuit.y

Like numerals indicate corresponding parts in the several figures.

Referring to the drawin numeral, 5. designates a sli ing door that is intended to close a doorway or opening which leads into lthe elevator shaft or Well (not shown) at an elevator-landing. Alike door is provided at each of the variouslandings, said doors being disposed in the same vertical plane.

'The safety-circuit' closing and opening ats by referencetachrnent 6 (shown enlarged in Fig. 3) is employed in connection with each door and comprises a spring-pressed pin 6', that is su prorted for longitudinal movement in t e ame 7 and which when pressed inwardly b reason ofthe contact ofthe adjacent edge of the closed door with the projecting end of said pin serves to force the opposite end to contact in bridging connection with the terminal contacts 8 and 9 oi the said device to close the circuit at that oint in the safetycircuit, which latter circuit will be hereinafter described.

IOO

The electric current for driving the elevai tor is taken from supply conductors or mains 10 and 11 throu h va manually-controlled double-pole switc 12. There is also included 1n said conductors 10 and 11 fuses 13. The conductors 10 and 11 terminate in fixed or stationary-contacts 14 and 15, that are shown as bein electrically connected to a reversing-swim v16` through an interposed electrica ly-actuated switc device 17a and conductors 14' and 15', Whileconductors 1-7 17 -and 18 18 represent the armature and ieldfmagnet circuits, respectively, that lead from the reversing-switch to the motor 16'.

The reversin or controllin switch v16 (shown in dotte lines in Fig. 1) eing a wellknown t e and as its construction, arrangement, an scheme of circuits and connections with the motor form no part of this invention, it will be deemed unnecessary to describe the same. i

` The elevator-car (net shown) adapted to be electrically propelled'ordriven by the motorl throughsuitable cables and mechanismfwhile the starting and stopping of the motor is ordinarily effected by a cable operated from lthe car, which transmits a *normally open branch comprises conductors 19 19', that include in one of said conductors l resistance l20, the terminals of said circuit 'adapted to beengage of the movable switch mechanism for open-y ing and closing. of the supply-circuit that being arranged in operative relation with they master-switch 17 a.,

Referring now particularly tothe masterswitch-controlling device 17"', (see Fig. 2,) there is shown provided stationary contacts 14 and 1,5, the contact-faces of which are` preferably com osed of carbon and arranged inthe same' p ane and which are properly spaced on a supporting board or base 21 and leads to the reversing-switch and motor.

The moving switch mechanism `comprises a pair ofswitch-arms 22 22', that are arranged in spaced arallelism andwhich carry on their free en scarbon contact-faces23,

l that are adapted to engage `with the corre sponding contacts 14 and 15 when ina closed position. The arms 22 22 are pivotally supported, respectively, on the brackets 23',

v that project from the front of the board 21 and which form the terminals of the cond-uctors 14' and 15', that lead to the reversingswitch 16. The switch-arms thus ccnstructed and arranged are ada ted to fall away from the contacts 14 an 15 by the force of gravity, which tendency is assisted by springs 24, operatively arranged, respectively, in connection with said arms, as shown. Provision, however, is made to normally maintain the switch-arms 22 22' in a closed position by an electrically-operated detent means, which comprises a cross-ann 25, that is normally pressed upward against the shoulders 25', ,formed on the respective by the contact-faces A arms, said cross-arm being in turn supported and carried on the upper end of the core or plunger 26, that is adapted for vertical reciprocation in the helix or solenoid 27. The lower end of the core 26 of the solenoid also su ports a bridging contact-piece 28, that is a apted to contact in its `lowermost position with the contacts-29 and 30, which form, respectively, the contact-terminals of the dynamic brake or armature short circuit.

4Vlhen the solenoid of the master-switch is denergized, the core 26 is allowed to drop by vgravity or by the exertion yof spring force,

or by both, to thereby break the supply-cirv cuit and to cause at the same time the closing lof the short circuit of the armature.

Te provide a continuance of current-suply to the held-magnets of the motor 16', a ranch circuit formed of conductors 31 31' lead independentlyfrom. the main conductors 10 and 11 to the field-magnets of the motor in the manner shown and include a bridging contact-piece 3-2, that is carried by the core 26 of the master-switchand which slides on the contact-blocks 33 and 34 during the reciprocation of said core 26. Thus it' will beseenthat avery effective kind of dynamic brake may be obtained by the disconnection of the supply-main from the motor and the introduction of a short circuit to the armature of the motor, providing the said short circuit includes a proper amount of resistance and a suitable quantity of current is allowed to pass to the field-magnets after the regular main supply of current has been cut ofi.4 I will now describe the means for energizing and denergizing the solenoid of the master-switch. The operating-coil 27 is shown as being included in a subsidiary or safety circuit, .that comprises conductors 35 35', which include in circuit at the respective door-landings 4the door opening and closing attachments 6 and at a 'point adjacent to the motor the speed-limit-governing means 36 for said motor. The conductors 35 and v35' are l shown as bein connected to main feed-con ductors 10 a-n 11. It will therefore be ob# served that so long as the safety-circuit just referred to is closed the solenoid will remain energizedr and the core thereof will maintain a closure of the motorsfeed circuit and a break in the 'dynamic brake or short-circuit of the armature, whereas upon the denergization of said Vsolenoid by reason of the opening of the safety-circuit the motor-feed circuit will be Aautomatically disconnected and the armature short circuit will be established.

v37 designatesabank of lamps that are included in the safety-circuit and which serve not only to indicate the current strength in said circuit, but which prevent sparking at the points where said circuit is opened. The safety-circuit is shown as also includinga circuitmpening device operatedv by ya centrif- IOO IOS

l readilyT understood from trifugal governor device consistsof governorsprmgs 38, mounted on a horizontal shaft 39, said springs carrying the usual central'balls-40.

One end of this governor is attached' firmly lo the shaft, While the other end is connected to a sliding collar 41. The shaft 39 is provided on its extended portion with a: wormgear 42,'that in turn meshes-with a gear-wheel 43. The gear 43 is positioned to engage with the gear-wheel 44, mounted on the end of the armature-shaft, as shown.

45 designates a sector the face of which is provided arranged as shown, the same, being dis osed 1n range and directly beneath the pat Way fulcrumed to the sector. the lever 47 is operatively connected to and controlled by the sliding collar 41 of the governor.

By reason of the foregoing-described arrangement a speed-limiting means is` provided for the motor that serves to open the safety-circuit when the speed of the armature reaches a dangerous Ypoint when traveling in either direction. i

The operation of the safety devices will be the foregoing descriptlon. v

What I claim as new and useful is* v 1. In a safety system of theclass described, the combination with a motor and its independent controlling means, of a separate safety-circuit, an armature short circuit, opening and closing means for the safety-circuit independent of said motor-controlling means, and switch mechanism comprising means for opening and closing the motorsupply circuit, and for vthe reverse opening and closing of said short circuit;

2. In a safety system ofthe class described,

the combination with a motor'and its 'independent controlling means, of a motor-sulpply clrcult, speed-governing means yfor t e motor, a separate safety-circuit including said s eedovernin means o enin and closing means for the safety-circuitindependent yof the said motor-controlling means, and means also included controlling said su ply-circuit and for applying a dynamic 'bra re to the motor.

3. A safety system of the class described com rising a motor-supply circuit, a normal y closed safety-circuit, opening and closing means included in said circuit, a currentindicator. and spark-preventin means included in said circuit, and an elgectric switch arranged in operative relation to said safetycircuit and provided with meansv for opening and closing an armature short circuit for the motor.

with a centrall -arranged contact' portion 46 and insulated strip portions 46 in the safety-circuit for' 4. A safety system ofthe class described comprising a supply-circuit for a motor, an armature slidrt circuit therefor, an independent eld-circuit for the motor, means for opening and closing said supply-circuit, meansfor causing the reverse opening and closing of the short circuit, and means for establishing theV independent field-circuit to the motor.

`5-..Ina safety system of the class described, the combination with a motor and its pendent controlling means, of a motor-supply indecircuit, an armature having a pluralit' o circuits, one of which circuits is normal y open and provided with resistance, a swltc-h in each circuit for controlling the same independently of said motor-controlling means, and means for actuating the switches.

6. A safety system of the class described comlprising a, motor-supply circuit, a normal y energized magnetlc switch normally maintaining theA current-supply for the motor, an armature branch short circuit including said switch and ada lted to be closed upon the denergization of t e latter, a current-retaining circuit forfthe motor field-magnets, and means for energizing and` denergizing the magnetic switch from a remotewpoint.

7. A safety system of the class described comprising a motor-supply circuit, an armature short circuit, an independent field-circuit, a separate safety-circuit, a switch included in said safety-circuit and comprising means fori opening and closing the supply-circuit, for causing the reverse opening armature short circuit, and

a for establishing said independent field-circuitfor the motor, anda dooror gate actuated circuit opening and closing means included in said safetycircuit.

8. A safety system of the class described comprising a supply-circuit for a motor, an armature short circuit, an independent fieldcircuit, a separate safety-circult, motor-governing means included in said safety-circuit, and a switch also included in said safety-cir- 4cuit and comprising means for controlling all of said other circuits, and controlled itsel by said governing means. 9.` A safetysystem of the class described comprising a motor-supply circuit, an armature short circuit, a current-retaining branch for ,the field-magnets of the motor, a safetycircuit, a switch mechanism included in said safety-circuit and comprising means for controlling said other cirouits, kmeans independent of the usual motor-controlling means for opening and closin the'safet -circuit, and a speed-governor inc ude'd in t e sald safetyclrouit and operatively related to sald motor.

10. A' safety system of the class described comprising a motor-supply circuit, a safetycircuit, inotor-governin means included 1n said'safety-circuit, a swltch mechanism also included in said circuit and comprising means and closing of the loolv for opening and closing the motor-supply circuit,'an electrically-operated detent arranged in operative relation to said governing means for normally holding the switch mechanism in a closed position, and motor-armature vshort-circuit connections arranged to be controlled by said detent.

11. In a safety system for motor-propelled vehicles having a safety-closure and inde- Eendent motor-controlling means, the comination of a safety meohamsm having a oontrolling device operated solely from said closure and' comprising Ine/ans, independent `of said motor-controlling meansz for' opening and closing the power-suppl TAfor the motor, 15 and for simultaneously'app ying restraining means to the latter. l

In testimony' whereof I afliX my signature in presenceof tWo subscribingwitnesses` JOHN A. MILLER. Witnesses:

. G. P. MONTAGUE,

H; STERLING. 

